TransCore SmartPass AI1611, System Manual

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SmartPass® Integrated Reader 2450 MHz (High Voltage) System Guide
Transient factors could include passing traffic, local weather conditions, chain link
fences, and gates that could temporarily reflect RF signals.
RF Reflectors
The most common RF reflectors are metallic surfaces. RF signals are also somewhat
reflected by nonconducting materials such as dirt, wood, ice, asphalt, and cured
concrete. When nonconducting materials in the system environment become wet,
they reflect more RF signals.
Aiming and placing Smartpass are the two best controls of RF reflections. When
these actions alone cannot adequately control reflections, other techniques may be
needed. These techniques could include shielding, absorbing, handshake counts, or
barriers.
RF Refraction
When an RF signal enters any material, its direction of travel is altered by a few
degrees. Refraction of RF signals rarely affects system performance, except when
tags are mounted on or under surfaces where nonconducting materials are placed or
can accumulate between the tag and the antenna.
RF Diffraction
Diffraction occurs when RF signals are bent around objects allowing RF into areas
that would normally receive little or no signal. Metal poles, corners of buildings, and
metal housings in industrial environments often diffract signals.
Existing Interference
Interference from RF and electrical sources can degrade system performance. This
type of interference must be considered in the site design.
Existing interference at the site may be shielded, removed, or positioned further from
the source. Filters may be added to the system. Fluorescent lights, neon signs, nearby
radio stations, or power lines can interfere with the optimal functioning of the
system. Even the magnetic impulse noise from relays, whose opening and closing
control the operation of a gate, can disrupt the RF signal.
SmartPass and Tag Mounting Locations
SmartPass can be installed in many positions to provide the most accurate field, or
read zone, for the tags. SmartPass can be mounted to a round pole or to a flat surface,
such as a wall, ceiling, flat pole, or an overhead structure. The following sections
provide more information for different site configurations and show the preferred tag
mounting locations.
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